/Engine/Source/Runtime/Engine/Classes/Animation/CustomAttributesRuntime.h
Blend custom attribute values from 2 inputs, using per-bone weights
static void BlendAttributesPerBone ( const [UE::Anim::FStackAttributeContainer](API\Runtime\Engine\Animation\FStackAttributeContainer) & SourceAttributes1, const [UE::Anim::FStackAttributeContainer](API\Runtime\Engine\Animation\FStackAttributeContainer) & SourceAttributes2, const [TArrayView](API\Runtime\Core\Containers\TArrayView)< const float > WeightsOfSource2, [UE::Anim::FStackAttributeContainer](API\Runtime\Engine\Animation\FStackAttributeContainer) & OutAttributes )